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vecino

Member

Registered: 2022-12-10

Posts: 139

[SOLVED] NetworkManager and noprefixroute

Hi, I use NetworkManager on my router for network configuration. The problem is that NM automatically sets the noprefixroute parameter, which then gives me problems with dynamic routing (OSPF). I've read man NM and nmcli but haven't found what I'm looking for.

Please do you know how I can entertain noprefixroute ?

    vlan103@enp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc htb state UP group default qlen 1000
    inet 10.107.80.219/29 brd 10.107.80.223 scope global noprefixroute vlan103
       valid_lft forever preferred_lft forever

Last edited by vecino (2024-04-05 20:08:43)

Koatao

Member

Registered: 2018-08-30

Posts: 98

Re: [SOLVED] NetworkManager and noprefixroute

Hello,

Can you explain a bit more about how noprefixroute prevents you to configure OSPF on the router? Do you have a specific error?

Are you sure NetworkManager is the right tool to configure networks interfaces on a router with 802.1Q and dynamic routing setup?

Can you post NM configuration?
Can you post the routing tables?
What do you use to configure OSPF? What is the current configuration?

vecino

Member

Registered: 2022-12-10

Posts: 139

Re: [SOLVED] NetworkManager and noprefixroute

For dynamic routing I use Frrouting: https://frrouting.org/ and currently under development is this revision which changed the logic for noprefixroute commit: https://github.com/FRRouting/frr/commit … 5c608df8a3 . The setup for FRR and NM is standard there is no problem. I have been using it for years. The problem only came up now when FRR changed the logic to access noprefixroute. However, the NM developers defend that it is correct from their point of view.

Are you sure NetworkManager is the right tool to configure networks interfaces on a router with 802.1Q and dynamic routing setup?

Yes, you are right and I agree that NM is not ideal, but what else to use? Not much choice... maybe systemd-networkd? Or after all, we won't be writing bastardized scripts for the ip command in 2023. How do you solve this?

Koatao

Member

Registered: 2018-08-30

Posts: 98

Re: [SOLVED] NetworkManager and noprefixroute

Hi,
According to this post on stack exchange (unix.stackexchange.com), the noprefixroute flag is a default with NM.
But NM still creates a route for the prefix with the related interface.

For dynamic routing I use Frrouting: https://frrouting.org/ and currently under development is this revision which changed the logic for noprefixroute commit: https://github.com/FRRouting/frr/commit … 5c608df8a3 .

It supposed to « Add ability for the connected routes to know if they are a prefix route or not. ». It don't see how it enforce anything on what route might be advertised with OSPF or not. Without real explanation on how it affects OSPF configuration, there is no way to tell if this is a bug or a misconfiguration of some sort.

And I insist on the fact that the configuration of FRRouting, NM and the routing tables is necessary for us to understand what is what and how everything links together.

The temporary fix is to downgrade FFRouting to a working release, prior to the commit you identified.

Last edited by Koatao (2023-12-27 10:30:18)

vecino

Member

Registered: 2022-12-10

Posts: 139

Re: [SOLVED] NetworkManager and noprefixroute

Hi Koatao, thank you for your reactions. Yes, this is standard in NM and has been confirmed to me by their developers. I will not use NM on routers anymore - simple solution. I thought I could turn it off, but I can't.

FRRouting - It's simple, new versions - connected routes should mirror whats in the ip route show table for the interface addresses. noprefixroute specifies to the kernel don't create a connected route = not working OSPF (in most scenarios).

!
router ospf
 ospf router-id 10.***.**.*
 log-adjacency-changes
 network 10.***.80.**/29 area 0.0.0.0
 network 10.***.202.**/29 area 0.0.0.0
exit
!